Fuze for a bomb



June 13, 1961 s, w, BOOTH 2,987,998

FUZE FOR A" BOMB Filed June 8, 1948 s. w. BOOTH United States Patent 2,987,998 FUZE FOR A BfiMB Seth W. Booth, 3900 Hamilton St], Hyattsville, Md.

- Filed June 8, 1948, Ser. N0. 31,781

8.- Claims;. (.Cl. 102-702) (Granted under Title '35, US. Code (1952), see. 266) This invention relates to; a fuze arrangement for detonating an explosive charge arranged within an ordnance missile such, for example, as a bomb, projectile, or rocket and more particularly to an inertial controlled firing unit for a fuze in which the firing is accomplished by a voltage developed within the. unit upon impact of the missile with a target.

One ofthe objects of the present invention is to provide a newand. improved inertial controlled firing. means for a fuze employed in an ordnance missile and adapted to fire an explosive charge arranged within the missile by a voltage developed as a piston or weight is forcibly urged against a crystal stack upon impact of the missile with a target.

Another object is to provide a new and improved firing means for a fuze adapted. for use in. an ordnance missile for firing the explosive charge arranged therein as the inertial force applied alongthe axes of a crystal stack produces an electrical voltage when the fuze is in an armed condition and the missile is subjected to a sharp deceleration.

Another object is to provide a new and improved inertial controlled firing means for a bomb fuze in which a voltage of suflicient intensity is produced to fire an electroresponsive. detonator upon impact of the bomb with a target. 7

Another object is to provide a new and improved firing unit for a fuze adapted for use in an ordnance missile and in which a piezoelectric crystal element thereof is employed as. a source of electrical energy for firing an electroresponsive detonator as the missile strikes a target.

Still another object is to provide a piezo-electric firing device for a projectile or the like in which the firing circuit is armed during the free flight of the projectile.

A still further object is to provide a new and improved firing unit for a fuze which is economical to manufacture, reliable in operation and which possesses all the qualities of ruggedness and dependability in service.

Still other objects, advantages and improvements will be apparent from the following description, taken in connection with the accompanying drawing, of which:

FIG; 1 is a fragmentary sectional view of an ordnance missile and'nose fuze therefor, the fuze casing being partrotate. The fuze is armed when the propeller has. made a predetermined number of revolutions during the free flight of the bomb toward a target in the manner hereinafter described.

. The fuze 12 comprises anelongated body -15 secured to the bomb in any convenient manner as by threading the parts together, and extends a substantial distance into the explosive or burster charge 16 disposed within the casing 11.

Secured within one end of the body 15 in any suitable manner but preferably as by threaded engagement there.- with is the firing unit of the present invention generally indicated by the numeral 17. The firing unit comprises a casing 18 having acentrally disposed cylindrical bore 19 therein, Slideably arranged within the bore 19 is a piston or mass 21 composed of any suitable material for the purpose such, for example, as steel, the respective ends of the piston being of reduced diameter to provide bosses 22 and 23 i A laminated crystal stack generally indicated by the reference character 24 is disposed within the bore 19 and comprises a plurality of flexible crystals 25 and electrodes 26 and 27, one surface of the crystal stack having abutting engagement with a wall 28 defining the end of the bore 19, the other surface thereof being in abutting engagement with the boss 22 on the piston 21 and maintained in abutting engagement therewith in any suitable manner as by a spring 29. The spring 29 is secured to the casing 18 in any suitable manner but preferably as by a plate 30 and screws 31, the spring being in abutting engagement with the boss 23.

By this arrangement the inertia mass or piston is suspended between two elements, the flexible crystal stack providing one point of suspension and the spring 29- constituting the other. It will be understood, however, that the piston is free to move axially within the bore 19 when an inertial force is appliedthereto parallel to the axis thereof. Thus upon impact of the bomb with a target, the piston is urged forcibly against the crystal unit, such force being of suflicient strength to cause compressing or flexing of the elements comprising the crystal unit. When this occurs, a voltage is developed. which is proportionalto the rate of change of pressure applied to the crystal unit by the piston, the. voltage being of sufiicient intensity to fire anelectroresponsive detonator 32, FIG- The arming arrangement employed with the firingunit of the present invention and disposed within the fuze body 1y broken away and in section for. the purpose of. disclosing the firing unit of'the present invention;

FIG. 2 illustrates in diagrammatic form the electrical circuits and instrumentalities employed with the firing unit of FIG. 1 according to a preferred embodiment of the invention;

FIG. 3 isa view similar to FIG. 2 and illustrating another circuit arrangement suitable for use with the firing unit; and

FIGS. 4 and 5 are views showing alternative arrangements of the, firing unit.

Referring now to the drawing wherein like reference characters designate like parts throughout the several views and more particularly to FIG. 1 thereon which is illustrated an ordnance missile or bomb generally indicated by the numeral 10, comprising a casing 11, to which is secured a fuze 1'2. An arming wire 13 is preferably employed to prevent premature rotative movement of the arming propeller 14 of the fuze until the bomb has been released from an aircraft in flight, whereupon the arming wire is. detached from the propeller as the bomb falls away'frorn the aircraft and thus the propeller is free to 15 may be of any conventional construction such, for example, as a structure disclosed in the. copendi'ng. application of H. J. Phimley et a1 Serial No. 541,257,- filed- June 20, 1944, now Patent 2,719,486;

It will be understood, however, that the fuze is adapted to be maintained in a safe or unarmed condition during handling and transportation, and arming ofthe fuzewilh not occur until the bomb has been released from: an air craft in flight, and the propeller 14 has made a predeter mined number of revolutions; during the free flight of the bomb toward the target, i Y

When this occurs the normally open arming switch indicated by the numeral 3-3 is closed as the rod 34, FIG. 2", is moved forward by the spring 35, the contacts 3d and 37 of the switch being brought into engagement with a sleeve 38 arranged on the rod and composed of anyeleca trical conducting material suitable for the purpose such, for example, as brass or the like. a r a Whenthe fuze is. in an. unarmed condition, FIG. 2, the switch contacts-36 and 37 are. normally in engagement with a sleeve 39 arranged on the rod. 34. andcomposed of any insulating material. suitable for the purpose such for example, as Bakelite. From the foregoingdescription it will be apparent that a firing circuit will not be i 3 completed between the crystal 24 and the detonator 32 until the rod 34 has been moved forwardly.

When this occurs the firing circuit is completed to the detonator 32 by way of leads 41 connected to electrodes 26, conductor 42 connected to leads 41 and to one side of detonator, conductor 43 connected to the other side of detonator and to the switch contact 36, conducting sleeve 38 on rod 34, switch contact 37, and thence through conductor 44, one end thereof being connected to contact 37, the other end being connected to leads 45 secured to electrodes 27. From the foregoing arrangement it will be understood that upon impact of the bomb with the target, the piston 21 is urged forcibly against the crystal 24 as the forward motion of the bomb is suddenly arrested thereby causing a voltage to be generated in the crystal in proportion to the rate of change of pressure applied thereto by the piston, the voltage being of sufficient intensity to fire the detonator 32 and thus initiate explosion of the bomb.

Referring now to FIG. 3 there is illustrated a firing circuit similar to FIG. 2 in which a transformer 46 is employed, the transformer being disposed between the switch 33 and the crystal stack 24. The primary winding 47 of the transformer is arranged between and connected to conductors 42 and 43 and the secondary winding 48 of the transformer is connected to opposite sides of the detonator 32. as by conductors 51 and 52. By this arrangement the transformer is adapted to match the high impedance of the voltage generating circuit to the relatively low impedance of the detonator firing circuit.

In FIGS. 4 and 5 an alternative arrangement of the device is illustrated, which is designed to function and explode an ordnance missile when the missile strikes the target a direct or glancing blow, as the case may be. In this arrangement the device comprises a pair of voltage generating units 53 and 54, having a pair of crystals 55 and 56 associated therewith and a plurality of pistons 57 and 58 respectively in engagement with the crystals. It will be understood, that the pistons are maintained in engagement with their respective crystals in the same manner as is the case of the device of FIG. 1.

The voltage generating units 53 and 54 are adapted to be arranged within the ordnance missile in such a manner as to develop a voltage in either one or the other of the aforesaid crystals as the piston receiving the inertial force is forcibly urged against its respective crystal upon impact of the missile with a target. In the firing circuit employed for use in this form of the device it will be understood that the crystals are connected in parallel and thus the detonator incorporated in the firing circuit will be fired when a voltage is generated in either one or both of the crystals.

' Whereas the invention has been described in detail with respect to a bomb adapted to be dropped upon a target from an aircraft in flight, it will be understood, that it may be advantageously employed, if desired, with a projectile or rocket. While the device has been shown and described in connection with a propeller controlled arming means including an electrical safety switch, it will be understood that any safety means may be employed for maintaining the fuze in a safe condition until the missile has been launched or fired, as the case may be.

If desired, the safety features may be obtained by the use of either mechanically or electrically controlled means or both by having a circuit arrangement whereby the detonator is disposed in an open circuit when the fuze is in a safe condition, and the circuit to the detonator will remain open until the fuze has been actuated to an armed condition by either setback or centrifugal force. Delay firing may be obtained if desired by employing a detonator having a delay element associated therewith.

, From the foregoing description it will be apparent that the firing unit is primarily adapted to function the fuze when the ordnance missile strikes a target a head-on blow but, by the aforesaid arrangement, means are devised for functioning the tuze and exploding the missile when the missile strikes the target either a head-on or a glancing blow.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise then specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. I

What is claimed as new and desired to be secured by Letters Patent is:

1. A device of the character disclosed for firing an electroresponsive detonator arranged within a fuze body, a casing secured within said body, said casing having a bore therein, said bore opening from one end of said casing and being closed at the other end thereof, an inertial piston slideably disposed within said bore constructed and arranged to be moved when the fuze is subjected to a sharp deceleration, a piezo-electric voltage generating device disposed within the bore intermediate said piston and said closed end of said bore for generating a voltage suflicient to fire the detonator when the piston has been moved forcibly thereagainst in response to said deceleration, and means for preventing movement of said piston sufiicient to generate said voltage until said sharp deceleration has been received by the fuze.

2. In a device of the character disclosed for firing an electroresponisve detonator arranged within a fuze, a casing secured to said fuze, an inertial piston slideably disposed within said casing constructed and arranged to be moved when the fuze is subjected to a sharp deceleration, a piezo-electric voltage generating device disposed within the casing in abutting engagement with said piston for generating a voltage sufficient to fire said detonator when the piston has been moved forcibly thereagainst in response to said deceleration, and means including a plate secured to the casing for yieldably maintaining the piston in said abutting engagement with said generating device until the fuze has received said deceleration.

3. In a device of the character disclosed for firing an electroresponsive detonator arranged within a fuze, a casing secured to said fuze, an inertial piston slidably disposed within said casing and adapted to be moved when the fuze is subjected to a sharp deceleration, a piezoelectric crystal arranged within the casing in abutting engagement with said piston for generating a voltage suflicient to fire said detonator when the piston has been moved forcibly thereagainst in response to said sharp deceleration, and means including a spring secured to the casing for maintaining the piston in said abutting engagement with said crystal and thereby preventing substantial movement thereof until the fuze has received said deceleration.

4. In a firing unit for a fuze, in combination, an ordnance missile, a casing for said missile, an explosive charge arranged within said casing, a housing for said fuze secured to said casing, means including a propeller rotatably supported by said housing for arming the fuze when the propeller has made a predetermined number of revolutions during the free flight of the missile toward a target, a mass slideably arranged within the housing, piezo-electric means responsive to the inertial pressure of said mass for generating an electrical firing impulse as the missile strikes said target, a normally open firing circuit connected to said impulse generating means, means for closing said firing circuit as the fuze is armed, and an electroresponsive detonator included within said firing circuit for firing said explosive charge in response to said impulse.

5. In a firing device for a fuze adapted for use in an ordance missile, in combination, a casing, an explosive charge arranged within said casing, a housing for said fuze secured to the casing, a pair of piezo-electric crystals arranged within the housing, a first movable mass abutting one of said crystals, a second mass abutting the other of said crystals and movable in a direction at right angle to said first mass, and at least one additional mass engaging at least one of said crystals and movable at right angles to the direction of movement of said first and second masses, said masses being responsive to the impact of the missile with a target for generating a Voltage selectively and independently in each of said crystals as the mass is urged forcibly against the crystals in response to said impact in any direction, and an electroresponsive detonator connected to said crystals and operated by said voltage for firing said explosive charge.

6. In a firing device for a fuze adapted for use in an ordnance missile, in combination, a casing, an explosive charge arranged Within said casing, a container for said fuze and secured to the casing, means including a propeller rotatably supported on the container for arming the fuze during the free flight of the missile toward a target, a pair of piezo-electric crystals arranged Within said container, a plurality of pistons arranged for sliding movement about different axes and respectively associated with said crystals for generating an electrical firing impulse in at least one of the crystals as the pistons are selectively and forcibly urged thereagainst upon impact of the missile with said target, a normally open firing circuit connected to the crystals, means operatively connected to and controlled by said arming means for closing said firing circuit as the fuze is armed, and an electroresponsive detonator included within said firing circuit and operated by said impulse for firing said explosive charge upon said impact.

7. In a firing device for a fuze adapted for use in an ordnance missile, in combination, a casing, an explosive charge arranged Within said casing, a container for said fuze and secured to the casing, means including a propeller rotatably supported on the container for arming the fuze during the free flight of the missile toward a target, a mass slideably arranged Within the container, piezo-electric means responsive to the inertial pressure of said mass for generating an electrical firing impulse as the missile strikes said target, a normally open firing circuit connected to said impulse generating means, means operatively connected and controlled by said arming means for closing said firing circuit as the fuze is armed, an electroresponsive detonator included Within said firing circuit for firing said explosive charge in response to said impulse, and an impedance matching transformer included in the firing circuit for increasing the transfer of electrical energy from the impulse generating means to said detonator.

8. In a firing device for a fuze adapted for use in an ordnance missile, in combination, a casing, an explosive charge arranged Within said casing, a container for said fuze and secured to the casing, a pair of piezo-electric crystals arranged within said container, a plurality of pistons arranged for sliding movement about dilferent axes and respectively associated with said crystals for generating an electrical firing impulse in at least one of the crystals as the pistons are selectively and forcibly urged thereagainst upon impact of the missile with said target, a firing circuit connected to the crystals, and an elecnoresponsive detonator included Within said firing circuit and operated by said impulse for firing said explosive charge upon said impact.

References Cited in the file of this patent UNITED STATES PATENTS 2,164,638 Broeze et a1 July 4, 1939 2,404,553 Wales July 23, 1946 2,764,091 Hudson et al Sept. 25, 1956 FOREIGN PATENTS 506,280 France May 26, 1920 525,333 Great Britain Aug. 27, 1940 

